Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Trifluoroacetyl primaquine oxalate (M8506) was compared with primaquine phosphate for tissue schizontocidal action in rodent and simian malaria. In Plasmodium yoelii sporozoites infected mice, the causal prophylactic effects of M8506 at 5, 10 and 20 mg(base)/kg were 56.7%, 87.2% and 100%, respectively, comparable to those of primaquine (54.4%, 90.8% and 100%). In P. cynomolgi sporozoites infected rhesus monkeys 4 dosage regimens of the two agents were compared for radical curative effect. On the first day of treatment pyronaridine phosphate 10 mg(base)/kg twice a day were intramuscularly injected to eliminate erythrocytic stages of P. cynomolgi. At the dosage of 3.0 mg(base)/kg/day x 3, both M8506 and primaquine radically cured the monkeys. At 0.75 mg/kg/day x 3, 12 of 13 (92.3%) monkeys cured by M8506, 5 of 9 (55.6%) cured by primaquine. At 1.5 and 0.375 mg/kg/day x 3, the radical curative effects of M8506 were also better than those of primaquine. Since the toxicity of M8506 was significantly milder in mice, rats and dogs than that of primaquine, M8506 has potential as a tissue schizontocide.
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PMID:Tissue schizontocidal effect of trifluoroacetyl primaquine in Plasmodium yoelii infected mice and Plasmodium cynomolgi infected monkeys. 194 65

Trifluoroacetyl primaquine (M-8506), 6-methoxy-5-trifluoroacetyl-8-(4-methyl-butyl-amino)-aminoquinoline oxalate, synthesized by the Institute of Parasitic Diseases was compared with primaquine for tissue schizontocidal action and acute ig LD50. In P yoelii sporozoite infected mice, the protection rates with ig M-8506 5, 10 and 20 mg (base)/kg on the day of infection were 56.7, 87.2 and 100%, respectively. These were comparable to the protection rates with primaquine 5, 10 and 20 mg(base)/kg (54.4, 90.8 and 100%, respectively). The radical curative effect was conducted in P cynomolgi sporozoite infected Macaca mulatta. Since im pyronaridine 10 mg/kg b.i.d. (6 h apart) completely eliminated the parasites in monkeys infected with erythrocytic stages of P cynomolgi, the tissue schizontocidal activities of M-8506 and primaquine were observed by im administration of pyronaridine 10 mg/kg b.i.d. on d 1. M-8506 at 0.75, 1.5 and 3 mg/(kg.d) x 3d plus pyronaridine were given to 7, 4 and 2 infected monkeys with parasitemia respectively. All the monkeys, except one receiving 0.75 mg/(kg.d) x 3 d, were radically cured. Primaquine 0.75, 1.5 and 3 mg/(kg.d) x 3 d were administered to 3, 3 and 2 monkeys respectively. Two monkeys receiving primaquine 0.75 mg/(kg.d) x 3 d relapsed on d 42. The parasitemia reappeared earlier than that treated with M-8506 0.75 mg/(kg.d) x 3 d and relapsed on d 62. Because M-8506 is less toxic than primaquine in mice and more effective in radical treatment of simian malaria, further studies on trifluoroacetyl primaquine are worthy to be considered.
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PMID:[Tissue schizontocidal action and acute toxicity of trifluoroacetyl primaquine]. 210 91

In searching for efficient, safe and radically curative agent and causal prophylactics for malaria, seven 2-methyl-5-substituted phenoxy-6-methoxy-8-(1-methyl-4-aminobutylamino)-quinolines (II1-7) were synthesized and their antimalarial activities were compared with the corresponding 4-methyl substituted derivatives of primaquine. The starting material, 2-nitro-4-methoxy-5-bromo-acetanilide (III), was prepared from p-methoxy aniline through acetylation, bromination and nitration. III was then condensed with substituted phenols in the presence of potassium carbonate. The condensed products were subsequently hydrolyzed with dilute alcoholic hydrochloric acid to yield 2-nitro-4-methoxy-5-substituted phenoxy-aniline (V) which underwent Skraup's reaction with 2-butenal to provide the key intermediates 2-methyl-5-substituted phenoxy-6-methoxy-8-nitroquinolines (VI). These 8-nitroquinoline derivatives were reduced to 8-aminoquinoline derivatives (VII). The latter were condensed with 4-bromo-1-phthalimido-pentane and then hydrolyzed with hydrazine hydrate, the final products were obtained as oxalate or succinate. The structure of the target compounds and unknown intermediates were confirmed by elementary and spectral analysis. Primary biological evaluation showed that all compounds II1-7 were much less active than the 4-methyl substituted derivatives and slightly less active than primaquine in both causal prophylactic test against Plasmodium yoelii and suppressive antimalarial test against P. berhei.
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PMID:[Synthesis of 2-methyl-5-substituted phenoxy-primaquine and antimalarials activity]. 223 31

A randomized double blind study was performed to evaluate the tolerance and the acceptance of mefloquine alone (Lariam) compared to a combined drug regimen consisting of mefloquine, sulfadoxine and pyrimethamine (MSP; Fansimef) in the prophylaxis of malaria. 175 Europeans travelling to different malaria endemic areas received either mefloquine alone (250 mg/week) or its combination with sulfadoxine (500 mg/week) plus pyrimethamine (25 mg/week). One person taking mefloquine and two taking MSP discontinued the drug intake because of moderate clinical side effects. Mild and moderate adverse clinical reactions predominantly concerning the gastro-intestinal tract and the autonomous nervous system were reported with a significantly higher occurrence in the MSP group. With both prophylactic regimens, reversibly elevated liver enzyme activities (glutamate oxalate transaminase and glutamate pyruvate transaminase [GPT]) were observed after prophylaxis. The increase of GPT serum activity correlated significantly with relatively high GPT levels before prophylaxis in both groups. This finding suggests a limited use of both regimens in cases of liver dysfunction. One case of mefloquine-resistant Plasmodium falciparum malaria was observed from West Africa; this patient was cured by a standard regimen of chloroquine.
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PMID:Tolerance of mefloquine alone and in combination with sulfadoxine-pyrimethamine in the prophylaxis of malaria. 269 82

Phyllanthus niruri is a medicinal plant (commonly known as stone breaker) found in the tropics and other parts of the world. It is known for its capacity to block the formation of calcium oxalate crystals and kidney stone formation in urolithiasis. This plant has been used to treat hyperglycemia, hypertension, pain, and mild cases of malaria. We examined the geno-, cyto- and overall toxicity of P. niruri whole plant ethanolic extract. The extract was administered as a single dose of 30 or 300 mg/kg to laboratory rats by gavage, accompanied by negative (0.9% saline) and positive (10 mg/mL N-ethyl-N-nitrosourea) controls that were injected intramuscularly 48 h after extract administration. The ratio of polychromatic (PCE)/normochromatic erythrocytes (NCE) from femur bone marrow was scored for genotoxicity. Cytotoxicity was determined using descending concentrations (0.2-0.0125 g/mL) of the extract incubated with peripheral blood mononuclear cells. Lactate dehydrogenase release from damaged cells was determined and the CC(50) calculated. Subchronic administration of the extract at 30 or 300 mg/kg was done for 90 days to determine general toxicity. PCE:NCE (%) for the extract and negative control was 63, compared to 168 (positive control). The CC(50) was 26.3 mg/mL and hepato-renal toxicity after subchronic extract administration was nil. We conclude that ethanol extract of P. niruri is not cytotoxic or genotoxic, and is generally non-toxic on subchronic administration.
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PMID:Genotoxicity, cytotoxicity and toxicological evaluation of whole plant extracts of the medicinal plant Phyllanthus niruri (Phyllanthaceae). 2229 Apr 70

Pseudothrombocytopenia or artefactual thrombocytopenia is an abnormally low number of platelets due to their agglutination in a sample tube, with no ex vivo clinical translation. It occurs in ethylene diamine tetraacetic (EDTA) test tubes. Non-EDTA anticoagulants, such as citrate, fluoride oxalate, and heparin lithium, may be responsible for it, alone or in combination. It can occur in patients with autoimmune diseases, neoplasia, atherosclerosis, liver disease, or infections. We report the case of a 5-year-old child, who after falciparum malaria showed persistent thrombocytopenia. Further exploration has led to the conclusion of pseudothrombocytopenia due to three anticoagulants: EDTA, citrate, and fluoride oxalate.
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PMID:Anticoagulant-induced pseudothrombocytopenia after a plasmodium falciparum infection in a five-year-old child. 3137 44

During its intra-erythrocytic growth phase, the malaria parasite Plasmodium falciparum relies heavily on glycolysis for its energy requirements. Pyruvate kinase (PYK) is essential for regulating glycolytic flux and for ATP production, yet the allosteric mechanism of P. falciparum PYK (PfPYK) remains poorly understood. Here we report the first crystal structure of PfPYK in complex with substrate analogues oxalate and the ATP product. Comparisons of PfPYK structures in the active R-state and inactive T-state reveal a 'rock-and-lock' allosteric mechanism regulated by rigid-body rotations of each subunit in the tetramer. Kinetic data and structural analysis indicate glucose 6-phosphate is an activator by increasing the apparent maximal velocity of the enzyme. Intriguingly, the trypanosome drug suramin inhibits PfPYK, which points to glycolysis as a set of potential therapeutic targets against malaria.
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PMID:Pyruvate kinase from Plasmodium falciparum: Structural and kinetic insights into the allosteric mechanism. 3287 5